Packaged food and preparation method thereof

Abstract

The invention provides a packaged food and a preparation method thereof, and belongs to the technical field of food processing. The invention provides a packaged food and a preparation method thereof. The preparation method comprises the following steps: immersing a semi-finished product material sealed by a deformable outer package into a thermal medium for sterilization treatment; the sterilization treatment comprises the following steps: sequentially carrying out heating treatment in three stages, carrying out heat preservation treatment after the heating treatment in each stage, and carrying out cooling treatment after the heat preservation treatment in the third stage; the heat preservation temperature of each stage of heat preservation treatment is 109-116 DEG C, and the heat preservation pressure outside the outer package during each stage of heat preservation treatment is set to be 0.09-0.16 Mpa; the total heat preservation time of the heat preservation treatment in each stage is 17-22 minutes. According to the method disclosed by the invention, the sterilization effect of the packaged food can be ensured, the deformation of an outer package and the browning of contents after sterilization treatment are effectively avoided, and the quality and the taste of the packaged food are remarkably improved, so that the commercialized popularization and application of the packaged food are favorably promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and in particular to a packaged food and a preparation method thereof. Background Art

[0002] As an important part of the modern food industry, the production process of packaged food covers many key links such as sophisticated pretreatment, seasoning, sterilization and preservation technology, aiming to ensure the safety of the product, extend its shelf life, and cater to consumers' diversified pursuit of taste and nutrition.

[0003] At present, packaged foods made from agricultural products such as vegetables, fruits, and cereals are generally packaged in deformable outer packaging materials, such as aluminum packaging containers in the form of cups or cans, or packaging bags made of plastic, composite materials, etc. These packaging materials not only effectively isolate external pollution and maintain the freshness, flavor and quality of food, but are also easy to carry, store and transport. At the same time, the information labeling on the surface of the outer packaging provides consumers with a convenient way to identify and purchase.

[0004] For this type of packaged food, if the sterilization treatment is improper and the microorganisms are not fully inactivated, the outer packaging is prone to bulging, which is not conducive to extending the shelf life. In this regard, the more mature sterilization process is to process the materials through pretreatment, blending, filling and other processing methods to make semi-finished products with sealed packaging, and place them in a specific sterilization kettle, using the high-temperature penetration of heat media such as water or steam to sterilize the materials inside the outer packaging. During the sterilization process, the temperature in the sterilization kettle is heated once to a higher sterilization temperature (for example, 121-125°C), and the materials are kept warm for a long time (for example, 25-35 minutes) at this sterilization temperature to ensure that the microorganisms in the materials are fully inactivated, thereby extending the shelf life of the packaged food.

[0005] However, the sterilization process still has the following defects: on the one hand, long-term sterilization at high temperatures can easily cause browning of the materials inside the outer packaging, damaging the quality and taste of the food; on the other hand, during the sterilization process, the materials will expand at high temperatures, and the external pressure of the outer packaging cannot match the temperature changes, resulting in a large pressure difference between the inside and outside of the outer packaging, which in turn causes the outer packaging to deform or even break and leak, seriously restricting the commercial promotion and application of packaged food. Summary of the invention

[0006] Technical problems solved by the present invention:

[0007] In the prior art, in the preparation process of packaged fruits, vegetables, cereals and grains, the sterilization treatment temperature is high and the time is long, and the materials inside the outer packaging are prone to browning, which damages the quality and taste of the food. In addition, during the sterilization process, the materials expand at high temperatures, and the external pressure of the outer packaging cannot match the temperature change, resulting in excessive pressure inside and outside the outer packaging, causing the packaging to deform or even break and leak. Therefore, there is still a need for a method for preparing packaged food with an outer packaging that does not deform and has excellent quality.

[0008] In response to at least part of the above-mentioned defects, the present invention provides a packaged food and a preparation method thereof, which can fully inactivate microorganisms in packaged fruits, vegetables, cereals and grains foods, and change the process defects of high sterilization temperature and long time, and the inability of the external pressure of the outer packaging to match the temperature change, thereby overcoming the problems of packaged food being prone to browning after sterilization, and the outer packaging being deformed or even damaged and leaking.

[0009] The technical solution of the present invention is as follows:

[0010] 1. A method for preparing packaged food, comprising the steps of immersing the semi-finished product material after the deformable outer package is sealed in a hot medium for sterilization;

[0011] The sterilization treatment includes: heating treatment in three stages, heat preservation treatment after each stage of heating treatment, and cooling treatment after the third stage of heat preservation treatment;

[0012] The insulation temperature of each stage of insulation treatment is 109-116°C, and the insulation pressure outside the outer packaging during each stage of insulation treatment is set to 0.09-0.16Mpa;

[0013] The total insulation time of each stage of insulation treatment is 17 to 22 minutes.

[0014] 2. In the method for preparing packaged food as in item 1 or 2, the holding temperature in each stage of the holding treatment and the holding pressure outside the outer package are constant;

[0015] Optionally, in the second stage heat preservation treatment and the third stage heat preservation treatment, the heat preservation time and the heat preservation pressure outside the outer package are increased accordingly based on the increase of the heat preservation temperature in the previous stage heat preservation treatment;

[0016] Optionally, during each stage of the insulation treatment, the insulation pressure outside the outer packaging is set to (T-100) / 100Mpa, where T represents the insulation temperature value during the insulation treatment at the corresponding stage.

[0017] 3. In the preparation method of packaged food as in item 1, during the third stage of heat preservation treatment, the heat preservation temperature is set to 114-116°C, the heat preservation pressure outside the outer package is set to 0.14-0.16 MPa, and the heat preservation time is 7-9 minutes;

[0018] Optionally, during the first stage of heat preservation treatment, the heat preservation temperature is set to 109-111°C, the heat preservation pressure outside the outer package is set to 0.09-0.11Mpa, and the heat preservation time is 4.5-6min;

[0019] Optionally, during the second stage of insulation treatment, the insulation treatment temperature is 111-114°C, the insulation pressure outside the outer packaging is set to 0.11-0.14Mpa, and the insulation time is 5.5-7min.

[0020] 4. In the method for preparing packaged food according to any one of items 1 to 3, the heating time of the second stage heating treatment and / or the third stage heating treatment is ≤ 3 min;

[0021] Optionally, the initial temperature of the first stage heating treatment is room temperature.

[0022] 5. In the method for preparing packaged food according to any one of items 1 to 4, the sterilization treatment is carried out by using a water immersion sterilizer;

[0023] Optionally, the deformable outer packaging includes any one of an aluminum foil container, a plastic packaging bag, and a composite material packaging bag;

[0024] Optionally, the aluminum foil container is any one of a cup, a can or a bowl;

[0025] Optionally, the aluminum foil container is covered with an aluminum foil cover film, and the inner part of the aluminum foil container is covered with a PP film.

[0026] 6. In the method for preparing packaged food according to any one of items 1 to 5, the temperature and pressure of the cooling treatment are reduced in stages over time;

[0027] Optionally, the cooling treatment includes sequentially performing a first-stage cooling treatment and a second-stage cooling treatment after the third-stage heat preservation treatment;

[0028] Optionally, the temperature of the first stage cooling treatment is 74-76°C, and the cooling time is 8-10 minutes;

[0029] Optionally, the temperature of the second stage cooling treatment is 24-26° C., and the cooling time is 5-6 minutes.

[0030] 7. The method for preparing a packaged food according to any one of items 1 to 6, further comprising:

[0031] Pre-treating the raw materials to obtain pre-treated materials;

[0032] Mixing the pretreated material with the auxiliary material to obtain a mixed material;

[0033] The mixed material is filled into a deformable package and sealed to obtain a semi-finished product;

[0034] The semi-finished product materials are sterilized and post-processed in sequence to obtain packaged food.

[0035] 8. The method for preparing packaged food according to any one of items 1 to 7, wherein the raw materials include fruits, vegetables and / or grains; further, the fruits, vegetables and / or grains include at least one of quick-frozen corn kernels, quick-frozen carrots, quick-frozen broccoli, quick-frozen green beans or sugar natto;

[0036] Optionally, the auxiliary materials include at least one of glutinous rice flour, milk powder, cheese powder, vitamins or minerals.

[0037] 9. In the case of the method for preparing packaged food as in Article 8, where the raw material is quick-frozen corn kernels:

[0038] The pretreatment includes chopping and mixing the quick-frozen corn kernels, the chopping and mixing frequency is controlled to be 1700-1800 Hz, the chopping and mixing speed is controlled to be 40-50 rpm, and the chopping and mixing time is controlled to be 20-26 s;

[0039] Optionally, the mixing is performed under stirring conditions, and during the mixing process, the speed is controlled to be 15 to 45 rpm, the temperature is controlled to be 40 to 60° C., and the time is controlled to be 20 to 40 min;

[0040] Optionally, the post-processing includes quick freezing, wherein the quick freezing temperature is below -30°C and the quick freezing time is 7 to 8 hours.

[0041] 10. A packaged food prepared by the method of any one of 1 to 9 above.

[0042] The present invention has at least the following beneficial effects:

[0043] By adopting the preparation method of the present invention to prepare packaged food, the semi-finished product material after the deformable outer package is sealed is immersed in a hot medium for sterilization treatment, which is beneficial for the material to be heated evenly and more fully during the sterilization process, so as to achieve sufficient inactivation of microorganisms after the sterilization treatment, thereby avoiding the occurrence of outer package bulging, and promoting the extension of the shelf life of the packaged food.

[0044] What is particularly critical is that, during the sterilization process, the temperature is raised in three stages in sequence, and each stage of temperature rise is followed by a heat preservation treatment, and the third stage of heat preservation treatment is followed by a cooling treatment; wherein, the heat preservation temperature of each stage of heat preservation treatment is 109-116°C, and the heat preservation pressure outside the outer packaging during each stage of heat preservation treatment is set to 0.09-0.16Mpa, and the total heat preservation time of each stage of heat preservation treatment is 17-22min; the heat preservation temperature of each stage of heat preservation treatment, the heat preservation pressure outside the outer packaging and the total heat preservation time are adapted to each other, which is conducive to the dynamic matching of the internal pressure of the outer packaging and the external pressure during the heat preservation treatment process, and promotes the uniform distribution of the pressure inside and outside the outer packaging during the sterilization process, thereby inhibiting the deformation or even damage and leakage of the outer packaging; in addition, the heat preservation temperature, heat preservation pressure and total heat preservation time during each stage of heat preservation treatment are highly matched, which ensures that the microorganisms in the packaged food are fully inactivated, while preventing the material from browning due to excessively high temperature and excessively long heating, thereby improving the quality and taste of the product.

[0045] Therefore, according to the method of the present invention, the semi-finished product material sealed by the deformable outer packaging is immersed in a hot medium for sterilization treatment. By dividing the sterilization process into three stages of heating treatment and heat preservation treatment, and accurately matching the sterilization conditions of the heat preservation treatment in each stage, the sterilization effect of the packaged food after sterilization treatment can be ensured, and the deformation of the outer packaging and the browning of the contents can be effectively avoided, which significantly improves the quality and taste of the packaged food, so as to promote the commercialization and application of packaged food. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 This is a rendering of the contents of the corn cheese packaged food prepared in Example 1 of the present application;

[0048] Figure 2 This is a rendering of the contents of the corn cheese packaged food prepared in Comparative Example 1 of the present application;

[0049] Figure 3 The renderings of the contents of corn cheese packaged food prepared in Example 1 and Comparative Example 3 of the present application (the upper part is Example 1, and the lower part is Comparative Example 2);

[0050] Figure 4The outer packaging of corn cheese packaged food prepared in Comparative Example 6, Comparative Example 5 and Example 1 of the present application (from left to right are Comparative Example 6, Comparative Example 5 and Example 1) is a rendering;

[0051] Figure 5 This is a rendering of the outer packaging of the corn cheese packaged food prepared in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0052] It should be understood that the specific embodiments given herein are for the purpose of explaining to those skilled in the art and are merely illustrative rather than restrictive.

[0053] In the following description, many specific details are set forth to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that specific details need not be adopted to practice the present invention. In other cases, well-known steps or operations are not described in detail to avoid obscuring the present invention.

[0054] It should be noted that in this article, the meanings of relevant terms are as follows:

[0055] The term "browning" refers to the phenomenon that after food is processed, stored or mechanically damaged, the amino compounds (such as proteins, amino acids, aldehydes, ketones, etc.) contained in it meet with reducing sugars and undergo a series of reactions to generate brown polymers. Temperature has a significant effect on the rate of browning reaction. This process is particularly common after agricultural foods such as fruits, vegetables, corn and grains are overheated.

[0056] The term "deformable outer packaging" refers to an outer packaging container made of a material with a certain deformation ability. It will deform under the action of external force, but the form of deformation is not rigid crushing, wrinkling or breaking, etc. For example, the deformable outer packaging can be an outer packaging container made of non-rigid materials such as tinplate rigid materials, flexible materials, etc.

[0057] The term "insulation" refers to placing materials in a relatively closed environment to reduce heat transfer so that the object maintains a constant current temperature for a predetermined period of time.

[0058] The term "water immersion sterilizer" refers to a sterilization device that uses hot water as a heat medium. During sterilization, the outer packaging of the semi-finished materials is completely immersed in hot water so that the materials inside the outer packaging are quickly and evenly heated, thereby performing high-temperature sterilization.

[0059] The term "spray sterilizer" refers to a sterilization device that uses hot water as a heat medium. During sterilization, the hot water is sprayed or injected onto the outer packaging surface of the semi-finished material to heat the material inside the outer packaging, thereby performing high-temperature sterilization.

[0060] The term "aluminum foil container" refers to an outer packaging container made of aluminum foil (an aluminum product with a thickness of less than 0.1 mm produced from aluminum ingots) as the main material. The surface of the aluminum foil has a dense oxide layer with relatively stable chemical properties. It can inhibit the growth of bacteria and microorganisms on its surface and is suitable for food outer packaging.

[0061] The term "chopping" refers to the process of chopping and mixing raw materials using the high-speed rotating blades or blunt knives of a chopper. During the chopping process, the blades or blunt knives rotate at a faster speed to cut and stir the materials, making them gradually become a fine and uniform paste.

[0062] Unless otherwise specified, the insulation pressure in this article refers to relative pressure, also known as gauge pressure.

[0063] The present invention will be described in detail below.

[0064] The embodiment of the present invention provides a method for preparing packaged food, comprising the steps of immersing a semi-finished product material sealed in a deformable outer package into a hot medium for sterilization;

[0065] The sterilization treatment includes: heating treatment in three stages, heat preservation treatment after each stage of heating treatment, and cooling treatment after the third stage of heat preservation treatment;

[0066] The insulation temperature of each stage of insulation treatment is 109-116°C, and the insulation pressure outside the outer packaging during each stage of insulation treatment is set to 0.09-0.16Mpa;

[0067] The total insulation time of each stage of insulation treatment is 17 to 22 minutes.

[0068] It should be understood that the semi-finished product material after the deformable outer packaging is sealed is immersed in a hot medium for sterilization. During the sterilization process, the heat preservation treatment after the temperature increase treatment at each stage plays a major role in sterilizing the material in the outer packaging.

[0069] According to the method for preparing packaged food provided by the embodiment of the present invention, the semi-finished material after the deformable outer packaging is sealed is immersed in a hot medium for sterilization treatment, for example, the semi-finished material after the deformable outer packaging is sealed can be immersed in hot water for sterilization treatment, so as to meet the thermal strength requirements of the material in the outer packaging, so that the material temperature is heated more evenly and fully, so as to achieve the full inactivation of microorganisms. In the sterilization process, the temperature is raised in three stages in sequence, and each stage is followed by a heat preservation treatment. After the temperature is raised in each stage, the material in the outer packaging is heated and expanded, causing the internal pressure of the outer packaging to increase. The heat preservation treatment is conducive to the dynamic matching of the internal pressure and the external pressure of the outer packaging, reducing the pressure difference between the inside and outside of the outer packaging, and then inhibiting the deformation and damage of the outer packaging; and the heat preservation treatment operation is conducive to the full conduction of heat to the material in the outer packaging, prompting the material to be heated evenly, so as to achieve the full inactivation of microorganisms; by accurately controlling the total duration of the heat preservation treatment in each stage, it is possible to ensure that the microorganisms are fully inactivated, and prevent the material from being overheated and browning, so as to improve the quality and taste of the packaged food.

[0070] It should be noted that the three-stage heating treatment can more easily balance the pressure difference inside and outside the outer packaging during each stage of insulation treatment, and fully inactivate the microorganisms of the material in the outer packaging and avoid browning. Under the conditions of setting the same insulation pressure outside the outer packaging and the total insulation time for each stage of insulation treatment, the two-stage heating treatment to reach the corresponding insulation temperature is likely to cause an imbalance in the pressure inside and outside the outer packaging, while the four-stage heating treatment to reach the corresponding insulation temperature will make the heating rate difficult to control, and the pressure inside and outside the outer packaging will be unbalanced, resulting in damage or browning of the material in the outer packaging, and seriously reducing the production efficiency.

[0071] During the three-stage sequential heating process, the terminal temperatures of the first stage heating treatment, the second stage heating treatment and the third stage heating treatment increase sequentially. Since the insulation temperature of each stage insulation treatment is 109-116°C, the terminal temperature after each stage heating treatment should be within the range of 109-116°C to meet the insulation temperature requirements of each stage insulation treatment; for example, the terminal temperature of the first stage heating treatment should reach above 109°C to meet the insulation temperature requirements of the first stage insulation treatment, such as the terminal temperature after the first stage heating treatment can be 109°C, the terminal temperature of the second stage heating treatment should be higher than 109°C and greater than the terminal temperature of the first stage insulation treatment to meet the insulation temperature requirements of the second stage insulation treatment, such as the terminal temperature after the second stage heating treatment can be 112°C, the terminal temperature of the third stage heating treatment should be below 116°C and greater than the terminal temperature of the second stage insulation treatment to meet the insulation temperature requirements of the third stage insulation treatment, such as the terminal temperature after the first stage heating treatment can be 116°C.

[0072] Since the heat preservation process in the embodiment of the present invention plays a major role in sterilizing the material in the outer packaging, the control of the heat preservation temperature, the heat preservation pressure outside the outer packaging and the heat preservation time during the heat preservation process is particularly critical; the heat preservation temperature of each stage of the heat preservation treatment is in the range of 109-116°C, the heat preservation pressure outside the outer packaging during each stage of the heat preservation treatment is set to 0.09-0.16Mpa, and the total heat preservation time of each stage of the heat preservation treatment is 17-22min, which is conducive to the full inactivation of microorganisms and prevents the browning of the material in the outer packaging and the deformation of the outer packaging; under the same outer packaging heat preservation pressure and total heat preservation time conditions, when the heat preservation temperature of the first stage of the heat preservation treatment is lower than 109°C, the heat intensity required for the material in the outer packaging is insufficient, and the microorganisms are easily inactivated insufficiently, and when the heat preservation temperature of the third stage of the heat preservation treatment is higher than 116°C, the material in the outer packaging is easily overheated and browned, affecting the quality and taste of the packaged food.

[0073] Moreover, under the same insulation temperature and total insulation time conditions, when the insulation pressure outside the outer packaging in the first stage of insulation treatment is lower than 0.09Mpa or when the insulation pressure outside the outer packaging in the third stage of insulation treatment is higher than 0.16Mpa, the pressure difference between the inside and outside of the outer packaging is too large, which is very easy to cause deformation.

[0074] In addition, under the same insulation temperature and insulation pressure conditions outside the outer packaging, a total insulation time of less than 18 minutes may easily lead to insufficient and uneven heating of the materials in the outer packaging, and insufficient inactivation of microorganisms; a total insulation time of more than 22 minutes may easily lead to excessive heating of the materials in the outer packaging, resulting in browning.

[0075] Therefore, by accurately matching the sterilization conditions of each stage of heat preservation treatment, the sterilization effect of the packaged food after sterilization can be ensured, and the deformation of the outer packaging and the browning of the contents can be effectively avoided, which is beneficial to improving the quality and taste of the packaged food.

[0076] In some optional embodiments, the insulation temperature in each stage of the insulation treatment and the insulation pressure outside the outer packaging are constant. In other words, the insulation temperature in each stage of the insulation treatment is maintained unchanged, and the insulation pressure outside the outer packaging is maintained unchanged. Since the pressure inside the outer packaging increases after the temperature rise treatment, the pressure difference inside and outside the outer packaging caused by the temperature rise can be balanced by maintaining the temperature unchanged for a period of time and matching the appropriate constant insulation pressure, thereby avoiding deformation or even damage of the outer packaging due to excessive pressure difference inside and outside the outer packaging caused by continuous temperature rise.

[0077] In some optional embodiments, in the second stage of heat preservation treatment and the third stage of heat preservation treatment, the heat preservation time and the heat preservation pressure outside the outer packaging are correspondingly increased based on the increase of the heat preservation temperature of the heat preservation treatment in the previous stage, so as to achieve the balance of the internal and external pressures of the outer packaging and ensure that the microorganisms are fully inactivated; specifically, the heat preservation temperature of the heat preservation treatment in the second stage or the third stage is higher than that in the previous stage, so it can adapt to the extended heat preservation time, so as to facilitate the full inactivation of microorganisms, and appropriately increase the heat preservation pressure outside the outer packaging to ensure that the internal and external pressures of the outer packaging can still be balanced after the temperature rises, thereby avoiding the deformation of the outer packaging. For example, the heat preservation time of the first stage of heat preservation treatment is 5 minutes, the heat preservation temperature is 109°C, and the heat preservation pressure outside the outer packaging is 0.09Mpa. Then, based on the increase of the heat preservation temperature of the first stage of heat preservation treatment, the heat preservation temperature of the second stage of heat preservation treatment can be 112°C, the heat preservation time can be correspondingly increased to 6 minutes, and the heat preservation pressure outside the outer packaging can be correspondingly increased to 0.12Mpa.

[0078] In some optional embodiments, during each stage of the heat preservation treatment, the heat preservation pressure outside the outer package is set to (T-100) / 100Mpa, where T represents the heat preservation temperature value during the heat preservation treatment at the corresponding stage; for example, during the third stage of the heat preservation treatment, the heat preservation temperature is 116°C, and the heat preservation pressure outside the outer package is set to (116-100) / 100=0.16Mpa. Under this condition, it is more conducive to the heat preservation temperature and the heat preservation pressure outside the outer package to accurately match during the heat preservation treatment, so as to promote the balance of pressure inside and outside the outer package, prevent the outer package from deformation and damage, and within the total heat preservation time under the same conditions, it can ensure that the microorganisms are fully inactivated, while further improving the quality and taste of the packaged food, thereby promoting the commercial application of packaged food.

[0079] While satisfying the total insulation time of each stage of insulation treatment being 18 to 20 minutes, in some optional embodiments, during the third stage of insulation treatment, the insulation temperature is set to 114 to 116°C, the insulation pressure outside the outer package is set to 0.14 to 0.16Mpa, and the insulation time is 7 to 9 minutes; for example, the insulation temperature of the third stage of insulation treatment can be set to 114°C, 115°C, 116°C or any insulation temperature value within the range of 114 to 116°C, the insulation pressure outside the outer package can be set to 0.14Mpa, 0.15Mpa, 0.16Mpa or any insulation pressure value within the range of 0.14 to 0.16Mpa, and the insulation time can be 7min, 8min, 9min or any time value within the range of 7 to 9min.

[0080] While satisfying the total insulation time of each stage of insulation treatment being 17 to 22 minutes, in some optional embodiments, during the first stage of insulation treatment, the insulation temperature is set to 109 to 111°C, the insulation pressure outside the outer package is set to 0.09 to 0.11 MPa, and the insulation time is 4.5 to 6 minutes; for example, the insulation temperature of the first stage of insulation treatment can be set to 109°C, 110°C, 111°C or any insulation temperature value within the range of 109 to 111°C, the insulation pressure outside the outer package can be set to 0.09 MPa, 0.10 MPa, 0.11 MPa or any insulation pressure value within the range of 0.09 to 0.11 MPa, and the insulation time can be 4.5 minutes, 5 minutes, 5.5 minutes, 6 minutes or any time value within the range of 4.5 to 6 minutes.

[0081] While satisfying the total insulation time of each stage of insulation treatment being 18 to 20 minutes, in some optional embodiments, during the second stage of insulation treatment, the insulation treatment temperature is 111 to 114°C, the insulation pressure outside the outer packaging is set to 0.11 to 0.14Mpa, and the insulation time is 5 to 6 minutes; for example, the insulation temperature of the second stage of insulation treatment can be set to 111°C, 112°C, 113°C, 114°C or any insulation temperature value within the range of 111 to 114°C, the insulation pressure outside the outer packaging can be set to 0.11Mpa, 0.12Mpa, 0.13Mpa, 0.14Mpa or any insulation pressure value within the range of 0.11 to 0.14Mpa, and the insulation time can be 5.5min, 6min, 6.5min, 7min or any time value within the range of 5.5 to 7min.

[0082] Such a design is more conducive to the precise matching of the insulation temperature, the insulation pressure outside the outer packaging and the insulation time during each stage of the insulation treatment, so as to take into account the pressure balance inside and outside the outer packaging, ensure the full inactivation of microorganisms, and inhibit the occurrence of browning of materials in the outer packaging, thereby avoiding deformation of the outer packaging of the packaged food and improving the quality and taste of the packaged food.

[0083] In some optional embodiments, the heating time of the second stage heating treatment and / or the third stage heating treatment is ≤3min; after the first stage heating treatment, the temperature reaches above 109°C for heat preservation treatment, at which time the material in the outer package is continuously heated, and the heating time of the second stage heating treatment and the third stage heating treatment is too long, which will cause the material to be overheated, and then cause the material in the outer package to brown. Therefore, the heating time of the second stage heating treatment and / or the third stage heating treatment is ≤3min, respectively, which can reach the insulation temperature required for the corresponding stage of heat preservation treatment in a short time, and at the same time avoid the material in the outer package from being overheated and browning. For example, the heating time of the second stage heating treatment and the third stage heating treatment can be 3min, 2.5min, 2min, 1.5min, 1min, 0.5min, 0.1min or any time value in the range of 0.1 to 3min.

[0084] In some optional embodiments, the initial temperature of the first stage of heating treatment is room temperature, and there is no need for additional preheating of the material, which helps to simplify the operating process, reduce costs, and improve the flexibility and adaptability of the sterilization treatment.

[0085] In some optional embodiments, the sterilization treatment is carried out by using a water immersion sterilizer; during the sterilization process using the water immersion sterilizer, the semi-finished product material after the outer packaging is sealed is completely immersed in hot water, and the outer packaging is evenly heated and sterilized by the conduction of hot water, so as to achieve overall heating and sterilization inside and outside the outer packaging, ensure that the sterilization effect inside and outside the food is consistent, and the microorganisms are fully inactivated. Compared with traditional spray sterilizers or high-temperature steam sterilizers, water immersion sterilizers as sterilization equipment have a more stable sterilization effect, higher thermal intensity and more uniform heat conduction, which can meet the uniform and sufficient heating of outer packaging of different shapes, and the insulation pressure outside the outer packaging is easier to control.

[0086] In some optional embodiments, the deformable outer packaging includes any one of an aluminum foil container, a plastic packaging bag, and a composite material packaging bag; the above-mentioned deformable outer packaging has good deformability and can adapt to food packaging requirements of different shapes and sizes.

[0087] Aluminum foil containers are preferably used. Aluminum foil has excellent barrier properties and can effectively prevent the penetration of oxygen, moisture and light, thereby extending the shelf life of food. It can also withstand high-temperature heating and is suitable for cooking methods such as steaming and baking. The aluminum foil container can be any of a cup body, a can body or a bowl body. The aluminum foil cup body is convenient for holding and drinking, suitable for single use or short-term storage. The aluminum foil can body usually has high strength and sealing performance, is convenient for stacking and storage, and is suitable for long-term storage and transportation. The aluminum foil bowl body usually has a larger capacity and a wider bottom, which is more convenient for eating, operation and cleaning.

[0088] Aluminum foil containers, whether cups, cans or bowls, have good deformability and can adapt to food packaging needs of different shapes and sizes. In order to achieve the sealing of the aluminum foil container, the aluminum foil container is covered with an aluminum foil cover film, and the aluminum foil container is covered with a PP film. The use of the aluminum foil cover film can significantly improve the sealing performance of the container. PP film, as a thermoplastic plastic, has good heat resistance and chemical stability. The PP film fits tightly on the inner wall of the aluminum foil container to form a protective barrier, which effectively prevents the material in the outer packaging from direct contact with the aluminum foil, avoiding possible chemical reactions or contamination.

[0089] In some optional embodiments, the temperature and pressure of the cooling treatment are reduced in stages over time, which can avoid excessive temperature differences between the inside and outside of the outer packaging and excessive pressure changes caused by rapid cooling, causing deformation or even damage to the outer packaging, thereby reducing the scrap rate of packaged food and improving production efficiency.

[0090] In some optional embodiments, the cooling treatment includes a first-stage cooling treatment and a second-stage cooling treatment in sequence after the third-stage heat preservation treatment, which is conducive to more precise control of the cooling process of the packaged food and avoiding excessive temperature difference between the inside and outside of the outer packaging, especially deformation of the outer packaging caused by the inability of external pressure to match temperature changes.

[0091] In some optional embodiments, the temperature of the first-stage cooling treatment is 74-76°C, and the cooling time is 8-10 minutes; for example, the temperature of the first-stage cooling treatment can be 74°C, 75°C, 76°C or any temperature value in the range of 74-76°C, and the cooling time can be 8 minutes, 9 minutes, 10 minutes or any time value in the range of 8-10 minutes.

[0092] In some optional embodiments, the temperature of the two-stage cooling treatment is 24-26°C, and the cooling time is 5-6 minutes; for example, the temperature of the two-stage cooling treatment can be 24°C, 25°C, 26°C or any temperature value in the range of 24-26°C, and the cooling time can be 5 minutes, 6 minutes or any time value in the range of 5-6 minutes.

[0093] In some optional embodiments, the preparation method further comprises:

[0094] Pre-treating the raw materials to obtain pre-treated materials;

[0095] Mixing the pretreated material with the auxiliary material to obtain a mixed material;

[0096] The mixed material is filled into a deformable package and sealed to obtain a semi-finished product;

[0097] The semi-finished products are sterilized and post-processed in sequence to obtain packaged food.

[0098] Depending on the raw materials, pretreatment may involve cleaning, cutting, peeling, de-coring, crushing, grinding and other treatments of the raw materials to remove impurities, adjust the raw material form, and improve the efficiency of subsequent processing and product quality. For example, for fruits and vegetables, washing, peeling, de-coring and cutting operations may be required, and for fresh corn, peeling, cleaning, threshing, quick freezing and other operations may be required. The pretreated material is mixed with auxiliary materials, wherein the auxiliary materials can be seasonings, preservatives, antioxidants, pigments, spices or nutrients, etc., to give the packaged food a specific flavor, taste, color or extend the shelf life of the packaged food. The mixed material is further filled into a deformable package (such as an aluminum foil container, a plastic bag, etc.), and the integrity of the package is ensured by a sealing process (sealing techniques such as heat sealing or pressure sealing can be used). After the semi-finished material obtained by sealing is sterilized and post-treated as described above, the packaged food can be obtained.

[0099] In some optional embodiments, the raw materials include fruits, vegetables and / or grains; specifically, the fruits, vegetables and / or grains may include at least one of quick-frozen corn kernels, quick-frozen carrots, quick-frozen broccoli, quick-frozen green beans or sweetened natto; the above raw materials are foods that easily turn brown when heated, and after being sterilized by the embodiments of the present invention, the browning of the raw materials can be inhibited, and their taste and quality can be ensured to be excellent.

[0100] In some optional embodiments, the auxiliary materials may include at least one of glutinous rice flour, milk powder, cheese powder, vitamins or minerals. In addition, the auxiliary materials may also include carotenoids (such as β-carotene); wherein the milk powder may be at least one of whole milk powder, skimmed milk powder or partially skimmed milk powder; the vitamins may be fat-soluble vitamins and / or water-soluble vitamins; the minerals may be at least one of calcium, iron, zinc and potassium; depending on the raw materials and the target packaged food types, the appropriate addition of the above auxiliary materials can maximize the taste of the product and further improve the nutritional value.

[0101] For example, when the raw material is quick-frozen corn kernels, the target packaged food may be corn cheese food, and the auxiliary materials in the preparation process may include at least one of glutinous rice flour, whole milk powder, cheese powder and β-carotene; glutinous rice flour can increase the viscosity and taste of the food, whole milk powder can enhance the milky flavor of the food, increase the nutritional value, and make the taste richer, cheese powder can give the food a rich cheese flavor and enhance the overall taste. The layered sense, β-carotene can add natural color to the food and provide nutritional fortification, which helps to enhance the visual effect and nutritional value of the packaged food.

[0102] In some optional embodiments, the packaged food is any one of seasoned corn food, seasoned fruit and vegetable food, candied natto food or corn cheese food. The raw materials of the above packaged foods are all ingredients that easily turn brown when heated. After being sterilized by the embodiments of the present invention, the browning can be inhibited and the taste and quality are excellent. For example, when the packaged food is corn cheese food, quick-frozen corn kernels are used as raw materials for preparation. The corn cheese food combines the sweetness of corn with the rich taste of auxiliary materials to become a nutritious food with diverse tastes. Its unique taste and flavor can meet the taste needs of different consumers and is suitable as breakfast, snacks or desserts.

[0103] In some optional embodiments, when the raw material is quick-frozen corn kernels, during the preparation of the corn cheese packaged food:

[0104] The pretreatment includes chopping and mixing the quick-frozen corn kernels. Through the chopping and mixing process, the quick-frozen corn kernels can be better mixed with the auxiliary materials to form a delicate and rich corn cheese. The chopping frequency is controlled to 1700-1800Hz, the chopping speed is controlled to 40-50rpm, and the chopping time is controlled to 20-26s; the above-mentioned chopping frequency, speed and time control can ensure that the corn kernels will not be over-broken, maintain a certain granularity, and make the corn cheese more compact and elastic. Furthermore, the mixing is carried out under stirring conditions. Mixing under stirring conditions can ensure that auxiliary materials such as glutinous rice flour, whole milk powder, cheese powder and corn kernels are fully integrated to form a uniform mixture. During the mixing process, the speed is controlled to 15-45rpm, the temperature is controlled to 40-60℃, and the time is controlled to 20-40min, so that the mixed material is more delicate and the taste is smoother; at the same time, the appropriate temperature can also stimulate the aroma of the auxiliary materials, making the sensory experience of packaged food better.

[0105] In some optional embodiments, the pretreated material is mixed with the auxiliary material in a sandwich pot, the temperature of the sandwich pot is controlled within the range of 50-60°C, the stirring speed of the sandwich pot is 15-45rpm, and the stirring time is 33-38min. By controlling the temperature, stirring speed and time of the sandwich pot, the viscosity of the material can be reduced to ensure the subsequent filling and sealing effect.

[0106] Further, the post-processing includes quick freezing, through which the temperature of the corn cheese can be quickly reduced, so that it can be quickly solidified and the taste and flavor can be locked. The quick freezing temperature of the quick freezing treatment is below -30°C (for example, any temperature value in the range of -30°C to -50°C), and the quick freezing time is 7 to 8 hours. The quick freezing temperature is below -30°C, which can ensure that the corn cheese reaches an ideal frozen state in a short time, while avoiding the formation of ice crystals that have an adverse effect on the taste. The quick freezing time is 7 to 8 hours, which can ensure that the corn cheese is fully cooled and its structure is stabilized, providing convenience for subsequent storage and transportation; at the same time, the quick freezing treatment can also extend the shelf life of the corn cheese, so that it can maintain a fresh taste and nutritional value for a long time.

[0107] Another embodiment of the present invention provides a packaged food, which is prepared according to the preparation method of the above embodiment.

[0108] In order to make the purpose, technical solutions and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. However, the described specific embodiments are only used to explain the present invention and are not used to limit the present invention.

[0109] Example 1

[0110] Provided is a method for preparing a corn cheese packaged food:

[0111] (1) Raw materials: quick-frozen corn kernels;

[0112] (2) Deformable outer packaging: an aluminum foil bowl covered with an aluminum foil cover film, the size of which is: 86.4*86.4*22.1 mm;

[0113] Aluminum foil sheet parameters: Brand: 8011; State: H22; Thickness: 0.095mm; Covered with 0.03mm PP film;

[0114] (3) Sterilization equipment: water immersion sterilizer;

[0115] The specific preparation process is as follows:

[0116] 1) 1 kg of quick-frozen corn kernels were put into a chopping machine for chopping to obtain pre-treated materials, wherein the chopping frequency was 1800 Hz, the chopping speed was 50 rpm, and the chopping time was 23 s;

[0117] 2) pouring the pretreated material into a sandwich pot, and then adding glutinous rice flour, whole milk powder, cheese powder, β-carotene and other auxiliary materials into the pot for mixing to obtain a mixed material; wherein the temperature of the sandwich pot is controlled at 50° C., the stirring speed of the sandwich pot is 30 rpm, and the stirring is carried out for 30 minutes;

[0118] 3) The mixed material is transferred to a filling device and filled into an aluminum foil bowl, and the semi-finished product is obtained by sealing; wherein the filling volume is about 91-93g, and the sealing adopts a heat sealing process, the heat sealing temperature is 255°C, and the heat sealing time is 2.5 seconds;

[0119] 4) Sterilization treatment: put the semi-finished product into a water immersion sterilizer, and start the insulation treatment from room temperature to the insulation temperature of 109°C through the first stage of heating treatment. The insulation time of the first stage of insulation treatment is 5 minutes, and the insulation pressure outside the outer package is set at 0.09 MPa; then carry out the second stage of heating treatment within 3 minutes, and start the insulation treatment when the temperature reaches 112°C. The second stage of insulation treatment is 6 minutes, and the insulation pressure outside the outer package is set at 0.12 MPa; then carry out the third stage of heating treatment within 3 minutes, and start insulation when the temperature reaches 115°C. The insulation time of the third stage is 8 minutes, and the insulation pressure outside the outer package is set to 0.15 MPa; after the third stage of insulation treatment, carry out the first stage of cooling treatment, the cooling temperature is 75°C, and the cooling time is 8 minutes; finally, carry out the second stage of cooling treatment, the cooling temperature is 25°C, and the cooling time is 5 minutes.

[0120] 5) The sterilized product is transferred to a quick-freezing warehouse, and is temporarily stored in the quick-freezing warehouse at -35°C for 8 hours for quick freezing to obtain a corn cheese packaged food.

[0121] Example 2

[0122] Compared with Example 1, the only difference is that the third stage of temperature treatment is increased to 116° C. and then insulation begins. The third stage insulation time is 7 minutes, and the insulation pressure outside the outer package is set to 0.16 MPa.

[0123] Example 3

[0124] Compared with Example 1, the only difference is that the third stage of temperature treatment is increased to 114° C. and then insulation begins. The third stage insulation time is 9 minutes, and the insulation pressure outside the outer package is set to 0.16 MPa.

[0125] Comparative Example 1

[0126] Compared with Example 1, the only difference is that the insulation temperature of the first stage insulation treatment is 112°C, the insulation temperature of the second stage insulation treatment is 115°C, and the insulation temperature of the third stage insulation treatment is 118°C.

[0127] Comparative Example 2

[0128] Compared with Example 1, the only difference is that the insulation temperature of the first stage insulation treatment is 107°C, the insulation temperature of the second stage insulation treatment is 110°C, and the insulation temperature of the third stage insulation treatment is 113°C.

[0129] Comparative Example 3

[0130] Compared with Example 1, the only difference is that the insulation time of the first stage insulation treatment is 5 minutes, the insulation time of the second stage insulation treatment is 8 minutes, and the insulation time of the third stage insulation treatment is 10 minutes.

[0131] Comparative Example 4

[0132] Compared with Example 1, the only difference is that the insulation time of the first stage insulation treatment is 3 minutes, the insulation time of the second stage insulation treatment is 5 minutes, and the insulation time of the third stage insulation treatment is 8 minutes.

[0133] Comparative Example 5

[0134] Compared with Example 1, the only difference is that the insulation pressure outside the outer packaging in the first stage of insulation treatment is 0.14Mpa, the insulation pressure outside the outer packaging in the second stage of insulation treatment is 0.17Mpa, and the insulation pressure outside the outer packaging in the third stage of insulation treatment is 0.20Mpa.

[0135] Comparative Example 6

[0136] Compared with Example 1, the only difference is that the insulation pressure outside the outer packaging in the first stage of insulation treatment is 0.06Mpa, the insulation pressure outside the outer packaging in the second stage of insulation treatment is 0.08Mpa, and the insulation pressure outside the outer packaging in the third stage of insulation treatment is 0.10Mpa.

[0137] Comparative Example 7

[0138] Compared with Example 1, the only difference is that the insulation temperature of the first stage insulation treatment is 112°C, the insulation temperature of the second stage insulation treatment is 115°C, and the insulation temperature of the third stage insulation treatment is 118°C; the insulation time of the first stage insulation treatment is 5 minutes, the insulation time of the second stage insulation treatment is 8 minutes, and the insulation time of the third stage insulation treatment is 10 minutes; the insulation pressure outside the outer packaging of the first stage insulation treatment is 0.08Mpa, the insulation pressure outside the outer packaging of the second stage insulation treatment is 0.12Mpa, and the insulation pressure outside the outer packaging of the third stage insulation treatment is 0.16Mpa.

[0139] Comparative Example 8

[0140] Compared with Example 1, the only difference is that the sterilization equipment is a high-temperature steam sterilizer.

[0141] Comparative Example 9

[0142] Compared with Example 1, the only difference is that no insulation treatment is performed after the first and second stage temperature rise treatments, that is, the third stage insulation treatment is started when the temperature is directly raised from the initial temperature to the insulation temperature of 115°C.

[0143] Comparative Example 10

[0144] Compared with Example 1, the only difference is that the first stage heat preservation treatment is not performed, and the second stage heat preservation treatment is performed directly after the first stage heat preservation treatment, that is, the second stage heat preservation treatment starts when the initial temperature is raised from room temperature to the heat preservation temperature of 112°C.

[0145] The parameter statistics of the heat preservation treatment process in each stage of the sterilization treatment of each embodiment are shown in Table 1 below:

[0146] Table 1. Statistical table of thermal insulation treatment parameters at each stage

[0147]

[0148]

[0149] The packaged foods after sterilization in each embodiment and the comparative example were tested for browning, microbial conditions and outer packaging deformation, and the test results are shown in Table 2 below:

[0150] Table 2. Test results of browning, microbial status and outer packaging deformation

[0151]

[0152]

[0153] It should be noted that "cfu" in Table 2 above refers to colony-forming units. Microorganisms <10 cfu means that the number of colonies that can be cultured in each milliliter or gram of sample is less than 10, which is a relatively low microbial content, indicating that the sanitary quality of the packaged food is good and the microorganisms are fully inactivated. In addition, in Comparative Examples 7, 9 and 10 in Table 2 above, the cover film ruptured and leaked during the sterilization process, the outer packaging was flooded, and the materials in the outer packaging were contaminated by the sterilization water and could not be tested for microbial conditions.

[0154] The packaged foods prepared in each embodiment and comparative example were subjected to sensory evaluation. During the sensory evaluation, 30 professionals blindly scored the packaged foods prepared in each embodiment and comparative examples 1 to 6 according to the following standards. The sensory evaluation scoring standards are as follows:

[0155] Table 3. Sensory evaluation scoring standard table

[0156]

[0157] The sensory evaluation results are shown in Table 4 below:

[0158] Table 4. Statistics of sensory evaluation results

[0159]

[0160] According to Table 1, Table 2 and Table 4, in Examples 1 to 3, the semi-finished product materials after the deformable outer packaging is sealed are immersed in a hot medium for sterilization treatment, and during the sterilization process, the temperature is raised in three stages in sequence, and each stage of temperature rise treatment is followed by insulation treatment, and the third stage of insulation treatment is followed by cooling treatment; the insulation temperature of each stage of insulation treatment is in the range of 109 to 116°C, and the insulation pressure outside the outer packaging during the insulation treatment in each stage is set in the range of 0.09 to 0.16Mpa, the total insulation time of each stage of insulation treatment is in the range of 17 to 22min, the materials in the packaged food do not produce browning, and the microorganisms are less than 10cfu, the outer packaging does not deform, the total sensory evaluation score is 44.3 points or more, and the quality and taste of the packaged food are excellent.

[0161] Compared with Example 1, the materials in the packaged food of Example 1 did not produce browning (such as Figure 1 As shown), the insulation temperature of the third stage insulation treatment of Comparative Example 1 is 118°C, which is too high, causing the material in the packaged food to brown (see Figure 2 ), which caused the smell, texture and taste of packaged food to deteriorate seriously. The total score of sensory evaluation was only 32.4 points, and the quality and taste of packaged food were poor.

[0162] Comparative Example 2 Compared with Example 1, the insulation temperature of the first stage of insulation treatment in Comparative Example 2 is 107°C. The insulation temperature is too low, resulting in insufficient inactivation of microorganisms in the packaged food, and microbial growth and swelling (see Figure 5 ), resulting in a shorter shelf life of the packaged food, and affected by the growth of microorganisms, the packaged food had a poor smell, texture and taste compared to Example 1, with a total sensory evaluation score of only 42.4 points, indicating that the quality and taste of the packaged food were poor.

[0163] Comparative Example 3 Compared with Example 1, the total insulation time of each stage of insulation treatment in Comparative Example 3 is 23 minutes, especially the insulation treatment time of the third stage exceeds 9 minutes, resulting in excessive heating of the materials in the packaged food to produce browning (such as Figure 2 As shown in the figure, the smell, texture and taste of packaged food are reduced, and the total score of sensory evaluation is only 41.4 points. The quality and taste of packaged food are poor.

[0164] Compared with Example 1, the total insulation time of each stage of insulation treatment in Comparative Example 4 is only 16 minutes, the total insulation time is too short, and the heat intensity of the sterilization process is insufficient, resulting in insufficient inactivation of microorganisms in the packaged food materials, and microbial reproduction causes swelling, which shortens the shelf life of the packaged food. In addition, affected by the reproduction of microorganisms, the smell, texture and taste of the packaged food are not as good as those in Example 1. The total score of the sensory evaluation is only 33.8 points, and the quality and taste of the packaged food are poor.

[0165] Compared with Example 1, the insulation pressure outside the outer packaging during the third stage of insulation treatment in Example 5 and the insulation pressure outside the outer packaging during the first stage of insulation treatment in Example 6 were not set within the range of 0.09-0.16Mpa, resulting in a large pressure difference between the inner and outer packaging, and deformation of the outer packaging (such as Figure 4 As shown, the outer packaging of the corn cheese packaged food prepared in Comparative Examples 5 and 6 was obviously deformed), the smell, texture and taste of the packaged food were not as good as those in Example 1, the total score of the sensory evaluation was lower than 44.3 points, and the quality and taste of the packaged food were poor.

[0166] Compared with Example 1, in Example 7, the insulation temperature, insulation time and insulation pressure outside the outer packaging during the third stage insulation treatment of Example 7 are seriously mismatched, and the pressure difference between the inside and outside of the outer packaging is too large, resulting in the cover film of the outer packaging directly bursting during the sterilization process. The material in the outer packaging is contaminated by the sterilization water and cannot be tested for microbial conditions.

[0167] In Comparative Example 8, compared with Example 1, the semi-finished product materials are not immersed in a hot medium for sterilization, but are sterilized by high-temperature steam sterilization in a high-temperature steam sterilizer, resulting in uneven and insufficient heating of the materials in the outer packaging, and microbial residues causing bulging of the outer packaging, which shortens the shelf life of the packaged food and poorer quality and taste.

[0168] Compared with Example 1, in Example 9, no insulation treatment was performed after the first two stages of heating treatment. Instead, the temperature was increased to 115°C for insulation treatment. The internal and external pressures of the outer packaging were difficult to dynamically match. The sudden change in pressure caused the cover film of the outer packaging to rupture directly during the sterilization process. The material in the outer packaging was contaminated by the sterilization water and could not be tested for microbial conditions.

[0169] Compared with Example 1, Example 10 is only subjected to the first stage of heating treatment without insulation treatment, and is directly heated to the insulation temperature required for the second stage of insulation treatment. The internal and external pressures of the outer packaging are difficult to dynamically match, and the sudden change in pressure causes the cover film of the outer packaging to rupture directly during the sterilization process. The material in the outer packaging is contaminated by the sterilization water and cannot be tested for microbial conditions.

[0170] It is worth noting that the overall scores of the sensory evaluation of Examples 1 and 2 are higher than that of Example 3. During the insulation treatment process at each stage of Examples 1 and 2, the insulation pressure outside the outer packaging is set to (T-100) / 100Mpa, and the insulation pressure and insulation temperature outside the outer packaging are precisely matched to ensure that the materials in the packaged food do not brown, and the microorganisms are fully inactivated. While the outer packaging does not deform, the total score of the sensory evaluation is increased to more than 48.8 points. The packaged foods have a strong corn aroma and milk flavor, good chewiness, soft and elastic texture, moderate sweetness, no greasy feeling, no peculiar taste or bitterness, and the quality and taste of the packaged food are better.

[0171] It can be seen that the preparation method according to the embodiment of the present invention can ensure the sterilization effect of packaged food, and effectively avoid the deformation of the outer packaging and the browning of the contents after sterilization, which significantly improves the quality and taste of the packaged food, so as to promote the commercialization and application of packaged food.

[0172] The various technical features described above can be combined arbitrarily. Although all possible combinations of these technical features are not described, any combination of these technical features should be considered to be covered by this specification as long as there is no contradiction in such combination.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing packaged food, characterized in that: The method comprises the steps of immersing the semi-finished product material sealed in the deformable outer package into a hot medium for sterilization; The sterilization treatment includes: heating treatment in three stages, heat preservation treatment after each stage of heating treatment, and cooling treatment after the heat preservation treatment in the third stage; The insulation temperature of each stage of the insulation treatment is 109-116°C, and the insulation pressure outside the outer packaging is set to 0.09-0.16Mpa during the insulation treatment at each stage; The total insulation time of each stage of insulation treatment is 17 to 22 minutes.

2. The method for preparing packaged food according to claim 1, characterized in that: The insulation temperature in each stage of the insulation treatment and the insulation pressure outside the outer packaging are constant; Optionally, in the second stage heat preservation treatment and the third stage heat preservation treatment, the heat preservation time and the heat preservation pressure outside the outer package are increased accordingly based on the increase of the heat preservation temperature in the previous stage heat preservation treatment; Optionally, during each stage of the insulation treatment, the insulation pressure outside the outer packaging is set to (T-100) / 100Mpa, where T represents the insulation temperature value during the insulation treatment at the corresponding stage.

3. The method for preparing packaged food according to claim 1 or 2, characterized in that: During the third stage of heat preservation treatment, the heat preservation temperature is set to 114-116° C., the heat preservation pressure outside the outer packaging is set to 0.14-0.16 MPa, and the heat preservation time is 7-9 minutes; Optionally, during the first stage of heat preservation treatment, the heat preservation temperature is set to 109-111° C., the heat preservation pressure outside the outer packaging is set to 0.09-0.11 Mpa, and the heat preservation time is 4.5-6 minutes; Optionally, during the second stage of insulation treatment, the insulation treatment temperature is 111-114° C., the insulation pressure outside the outer packaging is set to 0.11-0.14 MPa, and the insulation time is 5.5-7 min.

4. The method for preparing packaged food according to any one of claims 1 to 3, characterized in that: The heating time of the second stage heating treatment and / or the third stage heating treatment is ≤3min; Optionally, the initial temperature of the first stage heating treatment is room temperature.

5. The method for preparing packaged food according to any one of claims 1 to 4, characterized in that: The sterilization treatment adopts a water-immersion sterilization kettle for sterilization; Optionally, the deformable outer packaging includes any one of an aluminum foil container, a plastic packaging bag, and a composite material packaging bag; Optionally, the aluminum foil container is any one of a cup, a can or a bowl; Optionally, the aluminum foil container is covered with an aluminum foil cover film, and the inside of the aluminum foil container is covered with a plastic film.

6. The method for preparing packaged food according to any one of claims 1 to 5, characterized in that: The temperature and pressure of the cooling treatment are reduced in stages over time; Optionally, the temperature reduction treatment includes sequentially performing a first-stage cooling treatment and a second-stage cooling treatment after the third-stage heat preservation treatment; Optionally, the temperature of the first stage cooling treatment is 74-76° C., and the cooling time is 8-10 minutes; Optionally, the temperature of the second stage cooling treatment is 24-26° C., and the cooling time is 5-6 minutes.

7. The method for preparing packaged food according to any one of claims 1 to 6, characterized in that: The preparation method further comprises: Pre-treating the raw materials to obtain pre-treated materials; Mixing the pretreated material with the auxiliary material to obtain a mixed material; Filling the mixed material into a deformable package and sealing it to obtain the semi-finished product material; The semi-finished product material is subjected to the sterilization treatment and post-treatment in sequence to obtain packaged food.

8. The method for preparing packaged food according to any one of claims 1 to 7, characterized in that: The raw materials include fruits, vegetables and / or grains; further, the fruits, vegetables and / or grains include at least one of quick-frozen corn kernels, quick-frozen carrots, quick-frozen broccoli, quick-frozen green beans or sugar natto; Optionally, the auxiliary material includes at least one of glutinous rice flour, milk powder, cheese powder, vitamins or minerals.

9. The method for preparing packaged food according to claim 8, characterized in that: When the raw material is quick-frozen corn kernels: The pretreatment includes chopping the quick-frozen corn kernels, wherein the chopping frequency is controlled to be 1700-1800 Hz, the chopping speed is controlled to be 40-50 rpm, and the chopping time is controlled to be 20-26 s; Optionally, the mixing is performed under stirring conditions, and the speed is controlled to be 15 to 45 rpm, the temperature is controlled to be 40 to 60° C., and the time is controlled to be 20 to 40 min during the mixing process; Optionally, the post-processing includes quick freezing, the quick freezing temperature of the quick freezing is below -30°C, and the quick freezing time is 7 to 8 hours.

10. A packaged food, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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